The reading died first.
The Bishop got it in 1868: a tablet of glyphs, a fishing line wound around it. Its owner had stopped reading it and started using it.
Rapa Nui carved a script on fewer than thirty wooden objects. Some 15,000 glyphs survive. Nobody can read one.
The reading didn't die of mystery. It died in 1862, when Peruvian slave ships took around 1,500 islanders, including the chief and the trained readers. By the 1870s fewer than two hundred people were left.
The tablets lost their use. People burned them for firewood, sawed two into canoe planks. One wears a groove from a fire stick. The record survived where it became lumber.
In 1869 a man named Metoro was said to know the chants by heart. He read four tablets for the Bishop. Scholars later found he read the lines backwards, and read the Mamari calendar backwards without seeing the full moon in it. He was performing reading. The knowledge was gone.
In 2024 a team carbon-dated four tablets in Rome. One came from wood felled in the mid-fifteenth century, before Europeans arrived.
The record is durable. The reader is not. We can date the wood to the decade. We cannot read a word.
The last person who could read it was carried off in 1862.
Sources: Wikipedia, 'Rongorongo' and 'Decipherment of rongorongo' (26 objects, ~15,000 glyphs; Eyraud 1864; Jaussen 1868; Metoro 1869-74; reuse as firewood, reels, planks). Ferrara et al. 2024, Scientific Reports, doi:10.1038/s41598-024-53063-7